Hybrid subassembly for driving a vehicle, hybrid engine unit and hybrid driving method

Abstract

A hybrid sub-assembly (10) of a vehicle drive system comprises at least one primary shaft (12), at least one secondary shaft (16), a transmission (18) comprising at least one intermediate shaft (26) separate from the primary shaft (12) and the secondary shaft (16), and an electric motor unit comprising at least one reversible electric machine (56), and a coupling device (58) capable of assuming at least one intermediate coupling position in which an output shaft (57) of the reversible electric machine (56) is kinematically linked to the intermediate shaft (26), and a secondary coupling position in which the output shaft (57) of the reversible electric machine (56) is kinematically linked to the secondary shaft (16) without passing through the intermediate shaft (26).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a drive subassembly intended to be positioned between an engine, for example a heat engine, and a set of one or more drive wheels of a vehicle. It relates in particular, although not exclusively, to such a subassembly intended to equip a heavy goods vehicle, that is to say a road vehicle of more than 3.5 tonnes, in particular a road tractor, or a carrier. STATE OF PRIOR ART

[0002] Document AT520019B1 describes a powertrain assembly of a vehicle, comprising a primary shaft intended to be driven by an engine of the vehicle, a secondary shaft intended to drive a set of one or more drive wheels of the vehicle, and a transmission box comprising one or more primary gear wheels integral in rotation with the primary shaft or capable of being coupled to the primary shaft, a plurality of secondary gear wheels integral in rotation with the secondary shaft or capable of being coupled to the secondary shaft, and an intermediate shaft to which intermediate gear wheels are integral in rotation, the primary gear wheel(s) and the secondary gear wheels each meshing with a corresponding gear wheel among the intermediate gear wheels.The powertrain assembly further comprises a reversible electric machine kinematically linked to the intermediate shaft and capable of operating as a current generator to brake the intermediate shaft or as a motor for driving the intermediate shaft. Such an electric machine makes it possible to envisage different operating modes, and in particular a transient operation of the electric machine to brake or accelerate the intermediate shaft and promote the synchronization of the transmission box in the transmission ratio change phases, a motor operation to assist the drive of the main engine of the vehicle outside the ratio change phases and an electric generator operation, for the electrical supply of vehicle accessories or a battery, in particular in vehicle braking phases. This type of powertrain assembly is also described, for example, in EP3100891 A1.

[0003] GB1435517A describes a gearbox comprising an output shaft and a countershaft, and a gear train between the countershaft and the output shaft, comprising a first gear wheel secured to one of the two shafts and a second gear wheel capable of being secured to the other shaft by means of a dog clutch. A reversible electrical machine is permanently coupled to the countershaft and the coupling means are controlled to synchronize the speed of the second gear wheel and the dog clutch before their engagement.

[0004] In these devices, the intermediate shaft or countershaft is always connected to the shaft of the electric machine, which limits the possible operating modes. STATEMENT OF THE INVENTION

[0005] The invention aims to remedy the drawbacks of the state of the art and to propose better integration of an electric machine into an intermediate shaft of a transmission box, making it possible to envisage previously inaccessible operating modes.

[0006] To this end, according to a first aspect of the invention, a hybrid subassembly for driving a vehicle is proposed, of the type comprising: at least one primary shaft, at least one secondary shaft and a transmission box comprising at least one intermediate shaft separate from the primary shaft and the secondary shaft and toothed wheel sets for producing several transmission ratios between the primary shaft and the secondary shaft via the intermediate shaft. The hybrid subassembly also comprises an electromotive group comprising at least one reversible electric machine, and a coupling device which, in at least one intermediate coupling position, kinematically connects an output shaft of the reversible electric machine to the intermediate shaft.Remarkably, the coupling device in at least one secondary coupling position, kinematically connects the output shaft of the reversible electric machine to the secondary shaft without passing through the intermediate shaft.

[0007] In the secondary coupling position, the coupling device allows direct power transmission between the reversible electric machine and the secondary shaft without driving the intermediate shaft. This makes it possible to envisage various operating modes which will be described later, including: a permanent electric drive mode of the secondary shaft by the reversible electric machine operating as a motor, a transient mode for maintaining traction during gear changes, a pure regenerative braking mode minimizing the resistive mechanical torque. These operating modes are in addition to those accessible in the intermediate coupling position.

[0008] The coupling device may comprise a plurality of coupling and / or uncoupling positions, for example three distinct coupling positions, allowing power transmission from the reversible electric machine to the intermediate shaft or the secondary shaft according to different transmission ratios.

[0009] The reversible electric machine may in particular be a permanent magnet synchronous machine, an asynchronous machine, a variable reluctance electric machine or a variable reluctance synchronous electric machine, known as synchro-reluctant.

[0010] According to one embodiment, the coupling device, in at least one uncoupling position, simultaneously kinematically uncouples the output shaft of the reversible electric machine from the intermediate shaft and the secondary shaft. This position of the coupling device makes it possible to implement additional operating modes in which the electric machine is uncoupled, either because it is not necessary for the operation of the transmission box, or because it is used for other purposes, for example for driving another rotating member. The decoupling of the electric machine makes it possible to limit the inertia and the resistive torque at the intermediate shaft, and to relieve the guide bearings of its rotor, which increases their service life.

[0011] According to the invention, the coupling device comprises at least one coupling mechanism kinematically permanently connected to the output shaft of the reversible electrical machine, an intermediate speed reducer kinematically permanently connected to the intermediate shaft and a secondary speed reducer kinematically permanently connected to the secondary shaft. The secondary speed reducer comprises a reversing gear wheel guided in rotation by a guide bearing coaxial with the intermediate shaft.

[0012] The reversible electrical machine must preferably be sized so as to be fully operational for wide operating ranges in the various operating modes envisaged. Thus, it is preferentially provided that the reversible electrical machine meets one or more of the following criteria: the reversible electric machine is capable of continuously developing a motor torque greater than 300 Nm, and preferably greater than 350 Nm, in a speed range of more than 1000 rpm, and preferably more than 2000 rpm inclusive having a lower limit which is less than 6000 rpm, and preferably less than 5000 rpm, and an upper limit which is greater than 6000 rpm, preferably greater than 7000 rpm, and preferably greater than 9000 rpm; the reversible electric machine is capable of developing a resistive torque greater than 400 Nm and preferably greater than 450 Nm in a speed range of more than 3000 rpm, and preferably more than 4000 rpm having a lower limit which is less than 6500 rpm, and preferably less than 6000 rpm and an upper limit which is greater than 9000 rpm, and preferably greater than 10000 rpm, for 30 seconds;the reversible electric machine is capable of developing an engine torque greater than 50 Nm and preferably greater than 60 Nm in a speed range of more than 5500 rpm, and preferably more than 7000 rpm having a lower limit which is less than 5000 rpm, and preferably less than 4500 rpm and an upper limit which is greater than 10000 rpm, and preferably greater than 11000 rpm, for 5 seconds in transient gear change regime.;

[0013] In practice, the coupling device in the intermediate coupling position kinematically connects the output shaft of the reversible electric machine to the intermediate shaft with a so-called intermediate transmission ratio while the coupling device in the secondary coupling position kinematically connects the reversible electric machine to the secondary shaft with a so-called secondary transmission ratio. According to an exemplary embodiment, the coupling device meets one or more of the following criteria: the secondary transmission ratio is greater than 6, and preferably greater than or equal to 8; the intermediate transmission ratio is greater than 4, and preferably greater than or equal to 6 between the intermediate shaft and the output shaft of the reversible electric machine; the secondary transmission ratio is strictly greater than the intermediate transmission ratio, preferably with a factor greater than or equal to 1.5 between the secondary transmission ratio and the intermediate transmission ratio.

[0014] It may be advantageous to have several transmission ratios between the reversible electric machine and the intermediate shaft and / or between the reversible electric machine and the secondary shaft. For this purpose, one or more of the following arrangements may be made: the coupling device, in an additional intermediate coupling position, kinematically connects the reversible electric machine to the intermediate shaft with an additional intermediate transmission ratio distinct from the intermediate transmission ratio; the coupling device, in an additional secondary coupling position, kinematically connects the reversible electric machine to the secondary shaft with an additional secondary transmission ratio distinct from the secondary transmission ratio.

[0015] According to a particularly advantageous embodiment, the hybrid subassembly further comprises a power take-off member, capable of being driven at least by the reversible electric machine, preferably in one of the following ways: the power take-off member is permanently kinematically connected to the intermediate shaft; the power take-off member is kinematically connected to the intermediate shaft via the coupling device in the intermediate coupling position; the power take-off member is kinematically connected to the output shaft of the reversible electric machine via the coupling device in the intermediate coupling position.

[0016] According to this embodiment, the power take-off member can be coaxial with the intermediate shaft.

[0017] According to another particularly advantageous embodiment, the hybrid subassembly may comprise a power take-off member, capable of being driven at least by the reversible electric machine, the power take-off member being kinematically linked permanently to the output shaft of the reversible electric machine.

[0018] It is then possible to envisage driving the power take-off by the reversible electric machine without using the vehicle's main engine, which makes it possible to achieve rotation speeds significantly higher than 1000 rpm, for example higher than 1500 rpm, and where appropriate up to 5000 rpm.

[0019] According to a variant of the invention, the electromotive group may comprise two reversible electric machines each comprising a rotor with an output shaft rotating about an axis of rotation, the two output shafts meshing simultaneously on a common toothed wheel arranged parallel to the two axes of rotation, said common toothed wheel being kinematically linked in rotation, directly or indirectly via a gear, to the coupling device. In this way, the use of two reversible electric machines improves the traction capacity of the vehicle operating in the mode of permanent electric drive of the secondary shaft by the reversible electric machine.

[0020] In practice, the transmission box can advantageously include: one, or preferably several primary gear wheels capable of being coupled to the primary shaft, for example by one or more coupling and uncoupling mechanisms, for example synchronizers or / dog clutches, several secondary gear wheels capable of being coupled to the secondary shaft, for example by one or more coupling and uncoupling mechanisms, for example synchronizers or / dog clutches, intermediate gear wheels permanently secured to the intermediate shaft, the primary gear wheel(s) and the secondary gear wheels each meshing permanently with a corresponding gear wheel among the intermediate gear wheels to form the gear trains.

[0021] In practice, the transmission box comprises coupling mechanisms for alternately coupling each of the primary gear wheels to the primary shaft, and each of the secondary gear wheels to the secondary shaft. Where appropriate, the hybrid subassembly may further comprise a friction clutch, dry or wet, intended to be arranged between the primary shaft and the main engine.

[0022] Various configurations of the primary gears, secondary gears, intermediate shaft and rotor of the reversible electric machine are possible.

[0023] According to one embodiment, the primary shaft and the secondary shaft have axes of revolution which coincide. Alternatively, these axes are parallel and distant.

[0024] According to an exemplary embodiment, the output shaft of the reversible electric machine has an axis of revolution parallel to an axis of revolution of the intermediate shaft, one or more of the following characteristics preferably being achieved: the axis of revolution of the output shaft coincides with the axis of revolution of the intermediate shaft; the axis of revolution of the output shaft is distant from the axis of revolution of the intermediate shaft; the axis of revolution of the output shaft is distant from an axis of revolution of the primary shaft; the axis of revolution of the output shaft is distant from an axis of revolution of the secondary shaft.

[0025] According to an exemplary embodiment, the coupling device comprises an epicyclic gear train kinematically arranged between the output shaft and the secondary shaft.

[0026] According to different variants, the coupling device comprises one or more of the following coupling mechanisms: a dog clutch mechanism, a synchronizer mechanism, a clutch mechanism, preferably a friction clutch mechanism, preferably wet, a double friction clutch, preferably wet, a triple friction clutch, preferably wet.

[0027] In particular, a dog clutch mechanism without synchronization may be considered in cases where it is intended that the electric machine itself will be used to synchronize the coupling device with the associated toothed wheel.

[0028] According to one embodiment, the hybrid subassembly is equipped with a control unit for the reversible electric machine and the coupling device, and sensors capable of generating a signal representative of a speed of revolution of the intermediate shaft or of a member kinematically linked to it and a signal representative of a speed of revolution of the reversible electric machine or of a member kinematically linked to it. The control unit can in particular be implemented to synchronize the coupling device.Preferably, the control unit is capable, in a state of uncoupling of the coupling device, of controlling the reversible electric machine so that a relative rotation speed between the coupling member kinematically linked to the reversible electric machine and the coupling member kinematically linked to the intermediate shaft achieves a predetermined condition, and, when the predetermined condition is achieved, of controlling a coupling of the coupling device. The predetermined condition may for example be a zero relative rotation speed or a predetermined relative sliding speed.

[0029] According to another aspect of the invention, the latter comprises a hybrid power unit with a main engine, preferably internal combustion, and a hybrid subassembly as described above. The main engine is equipped with a main drive shaft linked to the primary shaft directly or via a clutch or a torque converter.

[0030] Preferably, the control unit of the coupling device is operable to control one or more of the following operating modes: a transient mode for maintaining traction during a gear change, in which the coupling device is positioned in the secondary coupling position, the main motor is decoupled from the intermediate shaft, and the reversible electric machine is controlled so as to generate a motor torque on the secondary shaft or to minimize a variation in speed of the secondary shaft while a gear change of the transmission is controlled; a pure regenerative deceleration mode without the intermediate shaft, in which the coupling device is positioned in the secondary coupling position, the secondary shaft is decoupled from the intermediate shaft and electrical energy is generated with the reversible electric machine operating as a generator;a direct electric drive mode without the intermediate shaft, in which the coupling device is positioned in the secondary coupling position, the intermediate shaft is uncoupled from the secondary shaft, and the reversible electric machine is driven. ;

[0031] Preferably, the control unit is operable to control one or more of the following operating modes: a reinforcement mode, in which the transmission box realizes one of the transmission ratios between the primary shaft and the secondary shaft by passing through the intermediate shaft, the main motor is powered so as to drive the primary shaft and to exert a main driving torque on the intermediate shaft, the coupling device is positioned in the intermediate coupling position, and the reversible electric machine generates a reinforcement driving torque on the intermediate shaft, of the same sign as the main driving torque;a recharging mode, in which the gearbox is positioned so as to connect the primary shaft to the intermediate shaft, the main motor is powered so as to drive the primary shaft and exert a main motor torque on the intermediate shaft, the coupling device is positioned in the intermediate coupling position, and kinetic energy is transformed into electrical energy with the reversible electric machine operating as a generator;a transient mode of synchronization of the intermediate shaft when changing one of the transmission ratios of the gearbox, in which the coupling device is positioned in the intermediate coupling position, the main motor is uncoupled from the intermediate shaft, then the reversible electric machine is controlled so as to bring the intermediate shaft to a set speed allowing the engagement of the secondary toothed wheel before recoupling the main motor to the intermediate shaft; an indirect electric drive mode, in which the coupling device is positioned in the intermediate coupling position and the main motor is uncoupled from the intermediate shaft while the intermediate shaft is kinematically linked to the secondary shaft, then the reversible electric machine is controlled according to a vehicle speed setpoint;a regenerative braking mode by the intermediate shaft, in which the coupling device is positioned in the intermediate coupling position, the main motor shaft is decoupled from the intermediate shaft and the reversible electric machine is driven to operate as a generator; a hybrid motor braking mode, in which the coupling device is positioned in the intermediate coupling position, one of the transmission ratios between the primary shaft and the secondary shaft passing through the intermediate shaft being engaged, the primary shaft being kinematically linked to the main motor shaft, and kinetic energy is transformed into electrical energy with the reversible electric machine operating as a generator and kinetic energy is transformed into heat with the main motor developing a resistive torque;a mode of driving a power take-off, in which the coupling device is positioned in the intermediate coupling position and the main motor is decoupled from the intermediate shaft, the intermediate shaft from the secondary shaft, and then the reversible electric machine is controlled to drive a power take-off coupled to the intermediate shaft. ;

[0032] According to another aspect of the invention, the invention relates to a method for hybrid driving a vehicle comprising a hybrid power unit according to the claim as previously described. With a control unit of the coupling device, one or more of the following operating modes are controlled: a transient mode for maintaining traction during a gear change, in which the coupling device is positioned in the secondary coupling position, the main motor is decoupled from the intermediate shaft, and the reversible electric machine is controlled so as to generate a motor torque on the secondary shaft or to minimize a variation in speed of the secondary shaft while a gear change of the transmission is controlled; a pure regenerative deceleration mode without the intermediate shaft, in which the coupling device is positioned in the secondary coupling position, the secondary shaft is decoupled from the intermediate shaft and electrical energy is generated with the reversible electric machine operating as a generator;a direct electric drive mode without the intermediate shaft, in which the coupling device is positioned in the secondary coupling position, the intermediate shaft is uncoupled from the secondary shaft, and the reversible electric machine is driven. ;

[0033] Preferably, one or more of the following operating modes are controlled with the control unit: a reinforcement mode, in which the transmission box realizes one of the transmission ratios between the primary shaft and the secondary shaft by passing through the intermediate shaft, the main motor is powered so as to drive the primary shaft and to exert a main driving torque on the intermediate shaft, the coupling device is positioned in the intermediate coupling position, and the reversible electric machine generates a reinforcement driving torque on the intermediate shaft, of the same sign as the main driving torque;a recharging mode, in which the gearbox is positioned so as to connect the primary shaft to the intermediate shaft, the main motor is powered so as to drive the primary shaft and exert a main motor torque on the intermediate shaft, the coupling device is positioned in the intermediate coupling position, and kinetic energy is transformed into electrical energy with the reversible electric machine operating as a generator;a transient mode of synchronization of the intermediate shaft when changing one of the transmission ratios of the gearbox, in which the coupling device is positioned in the intermediate coupling position, the main motor is uncoupled from the intermediate shaft, then the reversible electric machine is controlled so as to bring the intermediate shaft to a set speed allowing the engagement of the secondary toothed wheel before recoupling the main motor to the intermediate shaft; an indirect electric drive mode, in which the coupling device is positioned in the intermediate coupling position and the main motor is uncoupled from the intermediate shaft while the intermediate shaft is kinematically linked to the secondary shaft, then the reversible electric machine is controlled as a function of a vehicle speed setpoint;a regenerative braking mode by the intermediate shaft, in which the coupling device is positioned in the intermediate coupling position, the main motor shaft is decoupled from the intermediate shaft and the reversible electric machine is driven to operate as a generator; a hybrid motor braking mode, in which the coupling device is positioned in the intermediate coupling position, one of the transmission ratios between the primary shaft and the secondary shaft passing through the intermediate shaft being engaged, the primary shaft being kinematically linked to the main motor shaft, and kinetic energy is transformed into electrical energy with the reversible electric machine operating as a generator and kinetic energy is transformed into heat with the main motor developing a resistive torque;a mode of driving a power take-off, in which the coupling device is positioned in the intermediate coupling position and the main motor is decoupled from the intermediate shaft, the intermediate shaft from the secondary shaft, and then the reversible electric machine is controlled to drive a power take-off coupled to the intermediate shaft. ; BRIEF DESCRIPTION OF THE FIGURES

[0034] Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures. [ Fig. 1 ] There Figure 1 illustrates a hybrid drive subassembly of a vehicle according to a first embodiment. Fig. 2 ] There Figure 2 illustrates a hybrid drive subassembly of a vehicle according to a second embodiment. Fig. 3 ] There Figure 3 illustrates a hybrid drive subassembly of a vehicle according to a third embodiment. Fig. 4 ] There Figure 4 illustrates a hybrid drive subassembly of a vehicle according to a fourth embodiment. Fig. 5 ] There Figure 5 illustrates a hybrid drive subassembly of a vehicle according to a fifth embodiment. Fig. 6 ] There Figure 6 illustrates a hybrid drive subassembly of a vehicle following an example which does not fall within the subject matter for which protection is sought.

[0035] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. DETAILED DESCRIPTION OF EMBODIMENTS

[0036] On the Figure 1 a hybrid subset is illustrated 10 drive of a vehicle, comprising a primary shaft 12 intended to be driven by a prime mover 14 of the vehicle, for example a thermal engine, a secondary shaft 16intended to drive a set of one or more drive wheels of the vehicle (not shown), and a transmission box 18.

[0037] The main engine connection 14 to the primary shaft 12 may include a clutch 20 of any suitable type, e.g. a slipper clutch. The secondary shaft connection 16 to the vehicle wheels may include one or more drive axles.

[0038] The transmission box 18, housed inside a cavity 22 of a transmission case 24, has an intermediate shaft 26 to which intermediate toothed wheels are rotationally secured 28, 30, 32, 34, 36. Two primary gears 38, 40 coaxial with the primary shaft 12, each form a gear train with a corresponding toothed wheel 28, respectively 30,among the intermediate gear wheels. The meshing of the gear trains 38, 28 And 40, 30 between primary gears 38, 40 and the corresponding intermediate gears 28, 30 are permanent. A double synchronizer 41 three-position clutch allows either primary gear to be coupled 38, 40 to the primary shaft 12, and provides a neutral position in which none of the primary gears 38, 40 is not coupled to the primary shaft 12.

[0039] Secondary gear wheels 42, 44, 46, coaxial with the secondary shaft 16, also each form a gear train with a corresponding toothed wheel 32, 34, 36, respectively, among the intermediate gear wheels, one of the gear trains being reversing and comprising an intermediate wheel 48to achieve a reverse gear ratio. The meshing of the gear trains formed by the secondary gear wheels 42, 44, 46 and the corresponding intermediate gears 32, 34, 36 are permanent. A three-position dog clutch without synchronizers 50, positioned between two of the secondary wheels 44, 46, allows either coupling to the secondary shaft 16 either of the two associated secondary wheels 44, 46, either, in an intermediate neutral position, to maintain the associated secondary gear wheels 44, 46 decoupled from the secondary shaft 16.

[0040] In this embodiment, the axis of revolution 100 of the primary shaft 12 is aligned with the axis of revolution 200 with the secondary shaft 16, which allows the use of the end primary gear wheel 40 alternatively as primary wheel, associated with the primary shaft12 by the synchronizer 41, or as a secondary wheel associated with the secondary shaft 16. For this purpose, a dog clutch 52 three-position without synchronizers, positioned between the end primary wheel 40 and the secondary wheel 42, allows coupling to the secondary shaft 16 either the primary end wheel 40 either the secondary wheel 42, and also allows, in an intermediate neutral position, to maintain the end primary wheel 40 and the secondary wheel 42 decoupled from the secondary shaft 16.

[0041] This creates a transmission box 18 with six forward gears and potentially two reverse gears, which can be coupled to the secondary shaft output if necessary 16 to an epicyclic gear train (not shown) to obtain a twelve-speed gearbox.

[0042] Remarkably, the hybrid drive subset 10 is equipped with an electric motor group 5 comprising a reversible electric machine 56, whose output shaft 57 rotates around an axis of revolution 300, and a coupling device 58, including in this example a dog clutch mechanism 59 three-position without synchronizer and two gear reduction trains 60, 62, 64 66, 68. In a position of connection to the intermediate shaft 26, also called intermediate coupling position, the coupling device 58 performs a rotational coupling of the output shaft 57 with a so-called intermediate speed reducer 260 here comprising a toothed wheel 60 which permanently meshes with a toothed wheel 62 attached to the intermediate shaft 26.In a position connected to the secondary shaft, also called the secondary coupling position, the coupling device 58 performs a coupling of the output shaft 57 with a so-called secondary speed reducer 264, comprising a toothed wheel 64 which permanently meshes with a reversing gear wheel 66 which itself meshes permanently with a toothed wheel 68 attached to the secondary shaft 16. Remarkably, it can be predicted that the reversing gear 66 is guided in rotation by a guide bearing 69 coaxial with the intermediate shaft 26. The intermediate shaft 26 can then support the guide bearing 69. Finally, the coupling device 58, in a neutral position, holds the output shaft 57 decoupled from the gears 60, 64. Within the coupling device 58,the transition from the intermediate coupling position to the secondary coupling position is made via the coupling mechanism 59 controlled by a control unit 76.

[0043] If applicable, the intermediate shaft 26 is equipped with a power take-off 168, intended to allow coupling of one or more vehicle accessories, for example a winch, a pump or a tool. The power take-off 168 may be for example a transmission shaft comprising an external connection interface, for example a spline.

[0044] The drive shaft 57 illustrated on the Figure 1 is integral with the rotor of the reversible electric machine 56 and constitutes a motor shaft. Alternatively, the reversible electric machine can integrate a reducer between the motor shaft and the output shaft 57.

[0045] The reversible electric machine56 is powered by a battery 70 via a current converter 72 bidirectional, which allows the reversible electric machine to be powered 56 into a motor, and vice versa, to turn the reversible electric machine 56 as a generator to power the battery 70.

[0046] The reversible electric machine 56 is preferably a high voltage machine, powered for example at a nominal voltage between 300 Volts and 800 Volts, capable of delivering significant torque and power, as will be discussed later.

[0047] The control unit 76 allows you to control the reversible electric machine 56 and its coupling device 58. Sensors are connected to this control unit 78, 80, 82 to measure the output shaft revolution speed 57, of the intermediate shaft 26and the secondary shaft 16 or revolution speeds of elements permanently driven by these shafts. This control unit 76 can be integrated into a robotic gearbox control 18 which controls the opening and closing of the synchronizers 41, dog clutch mechanisms 50, 52, and where applicable the main clutch 20, to respond to a torque or speed instruction.

[0048] The electric machine 56 allows several modes of operation to be considered, as will be discussed later.

[0049] On the Figure 2 a hybrid subset is illustrated 10 according to a second exemplary embodiment of the invention, which differs from the exemplary embodiment of the Figure 1 by the fact that the coupling device 58 includes, in addition to the three-position dog clutch mechanism 59,a two-position dog clutch mechanism 159, which performs a rotational coupling of the output shaft 57 with a second intermediate speed reducer 360 comprising a toothed wheel 160 which permanently meshes with a toothed wheel 162 attached to the intermediate shaft 26. The transmission ratio achieved by the gearing of the gear wheels 160, 162 is different from the gear transmission ratio of the gear wheels 60, 62. The coupling mechanism 159, in a neutral position, holds the output shaft 57 decoupled from the gear wheel 160.

[0050] The person skilled in the art will understand, without it being necessary to illustrate it in detail, that he could, if necessary, multiply the transmission ratios between the output shaft 57and the intermediate shaft by adding speed reducers between the coupling mechanisms 59, 159 and the intermediate shaft 26. Similarly, it would be possible to multiply the transmission ratios between the output shaft 57 and the secondary shaft 16 by adding coupling mechanisms and speed reducers between the output shaft 57 and the secondary shaft 16.

[0051] The coupling mechanisms 59, 159 of the coupling device 58 can be of any type, including dog clutch with or without synchronization or friction. On the Figure 3 a third example of embodiment of the invention is thus illustrated, which differs from the example of embodiment of the Figure 1 by the fact that the coupling device 58 has a wet friction double clutch type coupling mechanism 259. On the Figure 4, the coupling device 58 has a wet friction triple clutch type coupling mechanism 359, achieving the same transmission ratios as the example of the realization of the Figure 2 . On the Figure 5 , a fifth exemplary embodiment of the invention has been illustrated, which differs from the exemplary embodiment of the Figure 3 by adding a reducer, here an epicyclic gear train 564, between the cogwheel 64 and the secondary shaft 16. Depending on the type of epicyclic gear train chosen, the reversing gear of the toothed wheels 66, 68 may remain necessary, or be integrated into the epicyclic gear train.

[0052] In the exemplary embodiments of the invention according to the figures 2 And 4, the coupling device comprises a plurality of coupling and uncoupling positions, in particular three distinct coupling positions, allowing power transmission from the reversible electric machine to the intermediate shaft or the secondary shaft according to different transmission ratios. The coupling device comprises in particular a first intermediate coupling position, a second intermediate coupling position otherwise called additional intermediate coupling position and a secondary coupling position. In the second intermediate coupling position, the coupling device 58 kinematically connects the reversible electric machine 56 to the intermediate shaft 26 with a second intermediate transmission ratio distinct from the first intermediate transmission ratio.

[0053] The various embodiments described have in common a coupling device 58 able to take at least one so-called intermediate coupling position in which the reversible electric machine 56 is kinematically connected to the intermediate shaft, and at least one secondary coupling position in which the reversible electric machine 56 is kinematically linked to the secondary shaft 16 without going through the intermediate shaft 26. These various couplings can be exploited to achieve a wide variety of operating modes, as will now be discussed.

[0054] First, several operating modes can be implemented while the coupling device 58 connects the output shaft 57 to the intermediate shaft 26.

[0055] In a transient mode of synchronization of the intermediate shaft during a gear change, the coupling device is positioned 58 in the intermediate coupling position, the main engine is uncoupled 14 of the intermediate shaft 26 either at the clutch level 20, either at the level of the dog clutch mechanism 41 , then we control the reversible electric machine 56 so as to bring the intermediate shaft 26 at a set speed allowing the engagement of the secondary gear wheel before re-coupling the main motor 14 to the intermediate shaft 26. During these transient phases, the reversible electric machine 56 thus allows the speed of revolution of the intermediate shaft to be adapted to the synchronization requirements when switching the dog clutch mechanisms 50, 52 or synchronizers 41.In these phases, the reversible electric machine can be used alternatively as an electric motor to increase the revolution speed of the intermediate shaft 26 or as a generator to reduce this speed. This adaptation of the speed of the intermediate shaft 26 allows you to reduce dog clutch or synchronization times, without using a gearbox brake.

[0056] In a recharging mode, one of the primary gears is coupled 38, 40 to the primary shaft 12, we power the main engine 14 so as to drive the primary shaft 12 and to exert a main driving torque on the intermediate shaft 26, the coupling device is positioned 58in the intermediate coupling position, and kinetic energy is transformed into electrical energy with the reversible electric machine operating as a generator. Recharging can take place while the intermediate shaft 26 drives the secondary shaft 16 or without connection to the secondary shaft 16.

[0057] In a reinforcement mode, one of the secondary gears 42, 44, 46 is coupled to the secondary shaft 16, one of the primary gears 38, 40 is coupled to the primary shaft, the main motor 14 is powered so as to drive the primary shaft 12 and to exert a main driving torque on the intermediate shaft 26, and the coupling device 58is positioned the intermediate coupling position or one of the intermediate coupling positions if there are several, and the reversible electric machine generates a reinforcing engine torque on the intermediate shaft, of the same sign as the main engine torque. The additional power input for the traction of the vehicle is achieved with a transmission ratio (for the examples of realization of the figures 1 , 3 And 5 ), two transmission ratios (for the examples of realization of the figures 2 And 4 ), or even more.

[0058] In a pure electric drive mode via the intermediate shaft 26, the coupling device is positioned 58 in the intermediate coupling position and the main engine is uncoupled 14 of the intermediate shaft 26 while one of the secondary gears 42, 44, 46is coupled to the secondary shaft 16, then the reversible electric machine is controlled according to a vehicle speed setpoint. For information purposes, to implement such an electric drive mode of the vehicle, it is advantageous for the reversible electric machine to be able to continuously develop an engine torque greater than 300 Nm, and preferably greater than 350 Nm, in a speed range of more than 1000 rpm, and preferably more than 2000 rpm inclusive having a lower limit which is less than 6000 rpm, and preferably less than 5000 rpm, and an upper limit which is greater than 6000 rpm, preferably greater than 7000 rpm, and preferably greater than 9000 rpm. With such an operating range, combined with several transmission ratios of between 4 and 8 produced by the meshing of the toothed wheels 32 And 42, 34 And 44, 60, 62 and where applicable 160, 162,we can consider electric operation of the vehicle in urban mode.

[0059] In a regenerative braking mode through the intermediate shaft, the coupling device 58 is positioned in the intermediate coupling position, the main engine 14 is decoupled from the intermediate shaft 26, at the clutch level 20 or synchronizers 41, one of the dogs 50, 52 is engaged to connect the intermediate shaft 26 to the secondary shaft 16 and the reversible electric machine 56 is driven to operate as a generator.

[0060] In a hybrid engine braking mode, the coupling device is positioned 58 in the intermediate coupling position, a kinematic connection is maintained between the main engine 14, the intermediate shaft 26 and the secondary shaft 16,we transform part of the kinetic energy transmitted by the secondary shaft 16 in electrical energy with the reversible electric machine 56 operating as a generator and transforming part of the kinetic energy transmitted by the secondary shaft 16 in heat with the main engine 14 developing a resistant torque. This operating mode makes it possible to achieve a greater braking torque than with the main motor 14 alone.

[0061] The reversible electric machine can also be used 56 in engine to drive the power take-off 168 while the transmission box 18 is in neutral position to interrupt the connection between the intermediate shaft 26 and the primary shaft 12 on the one hand, and between the intermediate shaft 26 and the secondary shaft 16 on the other hand.

[0062] Particularly advantageously, other modes of operation can be envisaged while the coupling device 58 connects the output shaft 57 to the intermediate shaft 26.

[0063] It is thus possible to implement a transient mode of maintaining traction during a gear change, in which the coupling device is positioned 58 in the secondary coupling position, the main engine is uncoupled 14 of the intermediate shaft 26, and we control the reversible electric machine 56 so as to generate engine torque on the secondary shaft 16 or to minimize a variation in speed of the secondary shaft while commanding a gear change of the transmission box 18 between the main engine 14 and the intermediate shaft 26 and / or between the intermediate shaft 26 and the secondary shaft16.

[0064] A pure regenerative braking mode can also be considered without the intermediate shaft 26, in which the coupling device is positioned in the secondary coupling position, the secondary shaft is uncoupled 16 of the intermediate shaft 26 by acting on the dog mechanisms 50, 52 and we generate electrical energy with the reversible electric machine 56operating as a generator. To optimally achieve this regenerative braking mode without the main motor, it is advantageous for the reversible electric machine to be able to develop a resistive torque greater than 400 Nm and preferably greater than 450 Nm in a speed range of more than 3000 rpm, and preferably more than 4000 rpm having a lower limit which is less than 6500 rpm, and preferably less than 6000 rpm and an upper limit which is greater than 9000 rpm, and preferably greater than 10000 rpm, this for at least 30 seconds.

[0065] The transient mode of maintaining traction during a gear change and the pure regenerative braking mode without the intermediate shaft 26 are transient operating modes, not intended to last more than thirty seconds. For information purposes, with a transmission ratio of around 8 between the output shaft 57and the secondary shaft 16, it is advantageous to size the reversible electric machine to develop a resistive torque greater than 400 Nm and preferably greater than 450 Nm in a speed range of more than 3000 rpm, and preferably more than 4000 rpm having a lower limit which is less than 6500 rpm, and preferably less than 6000 rpm and an upper limit which is greater than 9000 rpm, and preferably greater than 10000 rpm, for 30 seconds.

[0066] Finally, a direct electric drive mode can be implemented without the intermediate shaft 26, in which the coupling device 58 is positioned in the secondary coupling position and the intermediate shaft 26 is uncoupled from the secondary shaft 16 at the level of the dog mechanisms 50, 52,the reversible electric machine acting in a driving or regenerative manner depending on the acceleration or braking needs. This operating mode is less flexible than the electric drive mode with the intermediate shaft since the plurality of transmission ratios of the transmission box are not available 18. But it can be used in addition to the latter, by offering a direct transmission ratio between output shaft 57 and secondary shaft 16 higher than the transmission ratios using the gearbox 18. For example, we can develop two ratios with a value of around 4 and 6 respectively, with the dogs 50, 52 of the transmission box 18 combined with the gear train 60, 62 of the coupling device 58,and an additional transmission ratio having a value of the order of 8 by the gear train 64, 66, 68 of the coupling device 58.

[0067] On the Figure 6 an example is illustrated which does not fall within the subject matter for which protection is sought, which differs from the first embodiment by the use of two reversible electrical machines 56a And 56b, each electrical machine comprising a stator and a rotor having an output shaft capable of rotating around an axis.

[0068] Reversible electrical machines 56a, 56b are of the same type and are, for example, permanent magnet synchronous machines. Each electrical machine provides the same nominal mechanical power.

[0069] As can be seen on the Figure 6 , the first electric machine 56a present in the example described a rotor with a first output shaft 57rotating around a first axis of rotation X1, the second electric machine 56b has a rotor with a second output shaft 57 rotating around a second axis of rotation X2. In the example described, the axes of rotation of the reversible electric machines are parallel but not coincident, the two electric machines 56a, 56b not having their axes of rotation aligned.

[0070] The output shafts 57 two electric machines mesh simultaneously on a common toothed wheel 110 arranged between the axes X1, X2. The common cogwheel 110 is kinematically linked to the two output shafts and receives the engine torque supplied by the two electric machines, these being distributed around the common toothed wheel 110 so as to form a first speed reducer Z1, Z2. The common cogwheel 110is kinematically linked with a transmission shaft 55 specific to the coupling device 58 from this example using a second speed reducer Z3, Z4.

[0071] Similar to the first embodiment, the coupling device 58 has a dog clutch mechanism 59 three-position without synchronizer and two gear reduction trains 60, 62, 64 66, 68. In a position of connection to the intermediate shaft 26, also called intermediate coupling position, the coupling device 58 performs a rotational coupling of the transmission shaft 55 with a so-called intermediate speed reducer 260 here comprising a toothed wheel 60 which permanently meshes with a toothed wheel 62 attached to the intermediate shaft 26.In a position connected to the secondary shaft, also called the secondary coupling position, the coupling device 58 performs a coupling of the drive shaft 55 with a so-called secondary speed reducer 264, comprising a toothed wheel 64 which permanently meshes with a reversing gear wheel 66 which itself meshes permanently with a toothed wheel 68 attached to the secondary shaft 16.

[0072] According to a variant not illustrated, the power take-off organ 168 is positioned on the output shaft 57 of the reversible electric machine 56.

Claims

1. Hybrid sub-assembly (10) for driving a vehicle, having: - at least one primary shaft (12); - at least one secondary shaft (16); - a transmission gearbox (18) comprising at least one intermediate shaft (26) different from the primary shaft (12) and the secondary shaft (16) and sets of gear wheels (38, 28, 40, 30, 32, 42, 36, 48, 44, 46) for obtaining a plurality of gear ratios between the primary shaft (12) and the secondary shaft (16) via the intermediate shaft (26); - an electromotive unit comprising at least one reversible electric machine (56), and a coupling device (58) which, in at least one intermediate coupling position, kinematically connects an output shaft (57) of the reversible electric machine (56) to the intermediate shaft (26), wherein the coupling device (58), in a secondary coupling position, kinematically connects the output shaft (57) of the reversible electric machine (56) to the secondary shaft (16) without going via the intermediate shaft (26) and, wherein the coupling device (58) comprises at least one coupling mechanism (59, 159, 259, 359) permanently kinematically connected to the output shaft (57) of the reversible electric machine (56), an intermediate speed reducer (260, 360) permanently kinematically connected to the intermediate shaft (26) and a secondary speed reducer (264, 564) permanently kinematically connected to the secondary shaft (16), characterized in that the secondary speed reducer (264, 564) comprises a reversing gear wheel (66) rotationally guided by a guide bearing (69) that is coaxial with the intermediate shaft (26).

2. Hybrid sub-assembly (10) according to Claim 1, characterized in that the coupling device (58), in at least one uncoupling position, kinematically uncouples the output shaft (57) of the reversible electric machine (56) simultaneously from the intermediate shaft (26) and the secondary shaft (16).

3. Hybrid sub-assembly (10) according to any one of the preceding claims, having one or more of the following features: - the reversible electric machine (56) is capable of continuously providing a driving torque of greater than 300 Nm over a range of speeds spanning more than 1000 rpm, between a lower limit below 6000 rpm and an upper limit above 6000 rpm; - the reversible electric machine (56) is capable of providing a resistive torque of greater than 400 Nm, over a range of speeds spanning more than 3000 rpm, between a lower limit below 6500 rpm and an upper limit above 9000 rpm, for 30 seconds; - the reversible electric machine (56) is capable of providing a driving torque of greater than 50 Nm, over a range of speeds spanning more than 5500 rpm, between a lower limit below 5000 rpm and an upper limit above 10000 rpm, for 5 seconds in a transient gear change phase.

4. Hybrid sub-assembly (10) according to any one of the preceding claims, <b>characterized in that, in the intermediate coupling position, the coupling device (58) kinematically connects the output shaft (57) of the reversible electric machine (56) to the intermediate shaft (26) with an intermediate gear ratio, in the secondary coupling position, the coupling device (58) kinematically connects the reversible electric machine (56) to the secondary shaft (16) with a secondary gear ratio, and in that at least one of the following criteria is met: - the secondary gear ratio is greater than 6, preferably greater than or equal to 8; - the intermediate gear ratio is greater than 4, preferably greater than or equal to 6, between the intermediate shaft (26) and the output shaft (57) of the reversible electric machine (56); - the secondary gear ratio is strictly greater than the intermediate gear ratio, preferably with a factor greater than or equal to 1.5 between the secondary gear ratio and the intermediate gear ratio.

5. Hybrid sub-assembly (10) according to Claim 4, characterized in that, in an additional intermediate coupling position, the coupling device (58) kinematically connects the reversible electric machine (56) to the intermediate shaft (26) with an additional intermediate gear ratio that is different from the intermediate gear ratio.

6. Hybrid sub-assembly (10) according to any one of the preceding claims, <b>characterized in that it further comprises a power take-off member (168) that can be driven by at least the reversible electric machine (56), preferably in one of the following manners: - the power take-off member (168) is permanently kinematically connected to the intermediate shaft (26); - the power take-off member (168) is kinematically connected to the output shaft (57) of the reversible electric machine (56) by the coupling device (58) in the intermediate coupling position.

7. Hybrid sub-assembly according to any one of the preceding claims, characterized in that the coupling device (58) comprises a planetary gearset (564) arranged kinematically between the output shaft (57) and the secondary shaft (16).

8. Hybrid sub-assembly according to any one of the preceding claims, characterized in that the coupling device (58) comprises one or more of the following coupling mechanisms: - a dog mechanism (59, 159), - a synchronizer mechanism, - a clutch mechanism (259, 359), preferably a friction clutch mechanism, preferably a wet friction clutch mechanism, - a double friction clutch (259), preferably a wet double friction clutch, - a triple friction clutch (359), preferably a wet triple friction clutch.

9. Hybrid sub-assembly (10) according to any one of the preceding claims, characterized in that the electromotive unit comprises two reversible electrical machines (56a, 56b) each comprising a rotor with an output shaft (57) rotating about an axis of rotation (X1, X2), the two output shafts (57) meshing simultaneously with a common toothed wheel (110) arranged parallel to the two axes of rotation (X1, X2), said common toothed wheel (110) being kinematically linked in rotation, directly or indirectly via a gear, to the coupling device (58).

10. Hybrid sub-assembly (10) according to one of the claims 1 to 8, characterized in that it comprises a control unit (76) for controlling the reversible electric machine (56) and the coupling device (58), and sensors (78, 80, 82) capable of generating a signal representative of a speed of revolution of the intermediate shaft (26) or of a member kinematically connected thereto, a signal representative of a speed of revolution of the secondary shaft (16) or of a member kinematically connected thereto, and a signal representative of a speed of revolution of the reversible electric machine (56) or of a member kinematically connected thereto.

11. Hybrid engine unit comprising a main engine (14), preferably an internal combustion engine, with a main drive shaft, characterized in that it further comprises a hybrid sub-assembly (10) according to any one of the preceding claims, the main drive shaft being connected to the primary shaft (12) directly or via a clutch (20) or a torque converter.

12. Hybrid drive method for a vehicle comprising a hybrid engine unit according to claim 11, characterized in that, with a control unit (76) for controlling the coupling device (58), one or more of the following operating modes are managed: - a transient mode in which traction is maintained during a gear shift, in which the coupling device (58) is placed in the secondary coupling position, the main engine (14) is uncoupled from the intermediate shaft (26), and the reversible electric machine (56) is ordered to generate a driving torque on the secondary shaft (16) or to minimize a variation in speed of the secondary shaft (16) when a change in gear ratio of the transmission gearbox (18) is ordered; - a mode of pure regenerative deceleration without the intermediate shaft (26), in which the coupling device (58) is placed in the secondary coupling position, the secondary shaft (16) is uncoupled from the intermediate shaft (26) and electrical energy is generated with the reversible electric machine (56) operating as a generator; - a mode of direct electric drive without the intermediate shaft (26), in which the coupling device (58) is placed in the secondary coupling position, the intermediate shaft (26) is uncoupled from the secondary shaft (16) and the reversible electric machine (56) provides the drive.

13. Hybrid drive method according to the preceding claim, <b>characterized in that, with the control unit (76), one or more of the following operating modes are managed: - a reinforcement mode, in which the transmission gearbox (18) produces one of the gear ratios between the primary shaft (12) and the secondary shaft (16), via the intermediate shaft (26), the main engine (14) is supplied with power so as to drive the primary shaft (12) and exert a main driving torque on the intermediate shaft (26), the coupling device (58) is placed in the intermediate coupling position, and the reversible electric machine (56) generates a reinforcement driving torque on the intermediate shaft (26), with the same sign as the main driving torque; - a charging mode, in which the transmission gearbox (18) is positioned so as to connect the primary shaft (12) to the intermediate shaft (26), the main engine (14) is supplied with power so as to drive the primary shaft (12) and exert a main driving torque on the intermediate shaft (26), the coupling device (58) is placed in the intermediate coupling position, and kinetic energy is converted to electrical energy with the reversible electric machine (56) operating as a generator; - a transient mode of synchronization of the intermediate shaft (26) during a shift in one of the gear ratios of the transmission gearbox (18), in which the coupling device (58) is placed in the intermediate coupling position, the main engine (14) is uncoupled from the intermediate shaft (26), then the reversible electric machine (56) is ordered to bring the intermediate shaft (26) to a speed setpoint allowing engagement of the secondary gear wheel before recoupling the main engine (14) to the intermediate shaft (26); - an indirect electric drive mode, in which the coupling device (58) is placed in the intermediate coupling position and the main engine (14) is uncoupled from the intermediate shaft (26), while the intermediate shaft (26) is kinematically connected to the secondary shaft (16), then the reversible electric machine is controlled according to a speed setpoint of the vehicle; - a mode of regenerative braking via the intermediate shaft (26), in which the coupling device (58) is placed in the intermediate coupling position, the main drive shaft (12) is uncoupled from the intermediate shaft (26) and the reversible electric machine (56) is ordered to operate as a generator; - a hybrid drive braking mode, in which the coupling device (58) is placed in the intermediate coupling position, one of the gear ratios between the primary shaft and the secondary shaft (16) via the intermediate shaft (26) being engaged, the primary shaft (12) being kinematically connected to the main drive shaft, and kinetic energy is converted to electrical energy with the reversible electric machine (56) operating as a generator and kinetic energy is converted to heat with the main engine providing a resistive torque; - a power take-off (68) drive mode, in which the coupling device (58) is placed in the intermediate coupling position and the main engine is uncoupled from the intermediate shaft, the intermediate shaft (26) from the secondary shaft (16), then the reversible electric machine (56) is ordered to drive a power take-off (68) coupled to the intermediate shaft (26).

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